Expandable, angularly adjustable and articulating intervertebral cages

ABSTRACT

The embodiments provide various interbody fusion spacers, or cages, for insertion between adjacent vertebrae. The cages may contain an articulating mechanism to allow expansion and angular adjustment, and enable upper and lower plate components to glide smoothly relative to one another. The cages may have a first, insertion configuration characterized by a reduced size at each of their insertion ends to facilitate insertion through a narrow access passage and into the intervertebral space. In their second, expanded configuration, the cages are able to maintain the proper disc height and stabilize the spine by restoring sagittal balance and alignment. The intervertebral cages are able to adjust the angle of lordosis, and can accommodate larger lodortic angles in their second, expanded configuration. Further, these cages may promote fusion to further enhance spine stability by immobilizing the adjacent vertebral bodies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application No.62/355,619, filed Jun. 28, 2016, the entirety of which is hereinincorporated by reference.

FIELD

The present disclosure relates to orthopedic implantable devices, andmore particularly implantable devices for stabilizing the spine. Evenmore particularly, the present disclosure is directed to expandable,angularly adjustable intervertebral cages comprising articulatingmechanisms that allow expansion from a first, insertion configurationhaving a reduced size to a second, implanted configuration having anexpanded size. The intervertebral cages are configured to adjust andadapt to lodortic angles, particularly larger lodortic angles, whilerestoring sagittal balance and alignment of the spine.

BACKGROUND

The use of fusion-promoting interbody implantable devices, oftenreferred to as cages or spacers, is well known as the standard of carefor the treatment of certain spinal disorders or diseases. For example,in one type of spinal disorder, the intervertebral disc has deterioratedor become damaged due to acute injury or trauma, disc disease or simplythe natural aging process. A healthy intervertebral disc serves tostabilize the spine and distribute forces between vertebrae, as well ascushion the vertebral bodies. A weakened or damaged disc thereforeresults in an imbalance of forces and instability of the spine,resulting in discomfort and pain. A typical treatment may involvesurgical removal of a portion or all of the diseased or damagedintervertebral disc in a process known as a partial or total discectomy,respectively. The discectomy is often followed by the insertion of acage or spacer to stabilize this weakened or damaged spinal region. Thiscage or spacer serves to reduce or inhibit mobility in the treated area,in order to avoid further progression of the damage and/or to reduce oralleviate pain caused by the damage or injury. Moreover, these type ofcages or spacers serve as mechanical or structural scaffolds to restoreand maintain normal disc height, and in some cases, can also promotebony fusion between the adjacent vertebrae.

However, one of the current challenges of these types of procedures isthe very limited working space afforded the surgeon to manipulate andinsert the cage into the intervertebral area to be treated. Access tothe intervertebral space requires navigation around retracted adjacentvessels and tissues such as the aorta, vena cava, dura and nerve roots,leaving a very narrow pathway for access. The opening to the intradiscalspace itself is also relatively small. Hence, there are physicallimitations on the actual size of the cage that can be inserted withoutsignificantly disrupting the surrounding tissue or the vertebral bodiesthemselves.

Further complicating the issue is the fact that the vertebral bodies arenot positioned parallel to one another in a normal spine. There is anatural curvature to the spine due to the angular relationship of thevertebral bodies relative to one another. The ideal cage must be able toaccommodate this angular relationship of the vertebral bodies, or elsethe cage will not sit properly when inside the intervertebral space. Animproperly fitted cage would either become dislodged or migrate out ofposition, and lose effectiveness over time, or worse, further damage thealready weakened area.

Thus, it is desirable to provide intervertebral cages or spacers thatnot only have the mechanical strength or structural integrity to restoredisc height or vertebral alignment to the spinal segment to be treated,but also be configured to easily pass through the narrow access pathwayinto the intervertebral space, and then accommodate the angularconstraints of this space, particularly for larger lodortic angles.

BRIEF SUMMARY

The present disclosure describes spinal implantable devices that addressthe aforementioned challenges and meet the desired objectives. Thesespinal implantable devices, or more specifically intervertebral cages orspacers, are configured to be expandable as well as angularlyadjustable. The cages may comprise upper and lower plate componentsconnected by articulating expansion or adjustment mechanisms that allowthe cage to change size and angle as needed, with little effort. In someembodiments, the cages may have a first, insertion configurationcharacterized by a reduced size at their insertion ends to facilitateinsertion through a narrow access passage and into the intervertebralspace. The cages may be inserted in a first, reduced size and thenexpanded to a second, expanded size once implanted. In their secondconfiguration, the cages are able to maintain the proper disc height andstabilize the spine by restoring sagittal balance and alignment. It iscontemplated that, in some embodiments, the intervertebral cages mayalso be designed to allow the cages to expand in a freely selectable (orstepless) manner to reach its second, expanded configuration. Theintervertebral cages are configured to be able to adjust the angle oflordosis, and can accommodate larger lodortic angles in their second,expanded configuration. Further, these cages may promote fusion tofurther enhance spine stability by immobilizing the adjacent vertebralbodies.

Additionally, the implantable devices may be manufactured usingselective laser melting (SLM) techniques, a form of additivemanufacturing. The devices may also be manufactured by other comparabletechniques, such as for example, 3D printing, electron beam melting(EBM), layer deposition, and rapid manufacturing. With these productiontechniques, it is possible to create an all-in-one, multi-componentdevice which may have interconnected and movable parts without furtherneed for external fixation or attachment elements to keep the componentstogether. Accordingly, the intervertebral cages of the presentdisclosure are formed of multiple, interconnected parts that do notrequire additional external fixation elements to keep together.

Even more relevant, devices manufactured in this manner would not haveconnection seams whereas devices traditionally manufactured would havejoined seams to connect one component to another. These connection seamscan often represent weakened areas of the implantable device,particularly when the bonds of these seams wear or break over time withrepeated use or under stress. By manufacturing the disclosed implantabledevices using additive manufacturing, one of the advantages is thatconnection seams are avoided entirely and therefore the problem isavoided.

Another advantage of the present devices is that, by manufacturing thesedevices using an additive manufacturing process, all of the componentsof the device (that is, both the intervertebral cage and the pins forexpanding and blocking) remain a complete construct during both theinsertion process as well as the expansion process. That is, multiplecomponents are provided together as a collective single unit so that thecollective single unit is inserted into the patient, actuated to allowexpansion, and then allowed to remain as a collective single unit insitu. In contrast to other cages requiring insertion of external screwsor wedges for expansion, in the present embodiments the expansion andblocking components do not need to be inserted into the cage, norremoved from the cage, at any stage during the process. This is becausethese components are manufactured to be captured internal to the cages,and while freely movable within the cage, are already contained withinthe cage so that no additional insertion or removal is necessary.

In some embodiments, the cages can be made with a portion of, orentirely, with an engineered cellular structure that includes a networkof pores, microstructures and nanostructures to facilitateosteosynthesis. For example, the engineered cellular structure cancomprise an interconnected network of pores and other micro and nanosized structures that take on a mesh-like appearance. These engineeredcellular structures can be provided by etching or blasting to change thesurface of the device on the nano level. One type of etching process mayutilize, for example, HF acid treatment. In addition, these cages canalso include internal imaging markers that allow the user to properlyalign the device and generally facilitate insertion throughvisualization during navigation. The imaging marker shows up as a solidbody amongst the mesh under x-ray, fluoroscopy or CT scan, for example.

Another benefit provided by the implantable devices of the presentdisclosure is that they are able to be specifically customized to thepatient's needs. Customization of the implantable devices is relevant toproviding a preferred modulus matching between the implant device andthe various qualities and types of bone being treated, such as forexample, cortical versus cancellous, apophyseal versus central, andsclerotic versus osteopenic bone, each of which has its own differentcompression to structural failure data. Likewise, similar data can alsobe generated for various implant designs, such as for example, porousversus solid, trabecular versus non-trabecular, etc. Such data may becadaveric, or computer finite element generated. Clinical correlationwith, for example, DEXA data can also allow implantable devices to bedesigned specifically for use with sclerotic, normal, or osteopenicbone. Thus, the ability to provide customized implantable devices suchas the ones provided herein allow the matching of the Elastic Modulus ofComplex Structures (EMOCS), which enable implantable devices to beengineered to minimize mismatch, mitigate subsidence and optimizehealing, thereby providing better clinical outcomes.

In one exemplary embodiment, an expandable spinal implant is provided.The expandable spinal implant may comprise an upper plate componentconfigured for placement against an endplate of a first vertebral body,a lower plate component configured for placement against an endplate ofa second, adjacent vertebral body, an articulating mechanism connectingthe upper and lower plate components together and comprising anintermediate guide component, the intermediate guide component having aninternal cavity for receiving an actuator pin, and an actuator pincomprising a shaft and an enlarged head portion, the actuator pin beingconfigured to effect articulation of the upper and lower platecomponents relative to one another to angularly adjust the expandablespinal implant. The articulating mechanism may be configured to allowrolling movement of the upper and lower plate components relative to oneanother.

The spinal implant including the blocking pin may be manufactured by anadditive production technique, with the blocking pin being manufacturedas a separate component to reside inside but still be moveable withinthe cage. In some embodiments, the expandable spinal implant may be aPLIF (posterior lumbar interbody fusion) cage. The expandable spinalimplant may have a first configuration wherein the plate components areangled toward one another at an anterior portion, then parallel to oneanother in an intermediate configuration, and a second configurationwherein the plate components are locked together and are angled relativeto one another at a posterior portion. In the second configuration, theimplant adjusts the angle of lordosis, and restores the sagittal balanceand alignment of the spine.

Although the following discussion focuses on spinal implants, it will beappreciated that many of the principles may equally be applied to otherstructural body parts requiring bone repair or bone fusion within ahuman or animal body, including other joints such as knee, shoulder,ankle or finger joints.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure. Additional features of thedisclosure will be set forth in part in the description which follows ormay be learned by practice of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 illustrates a perspective view of an exemplary embodiment of anintervertebral cage in accordance with the present disclosure.

FIG. 2A illustrates an anterior view of the intervertebral cage of FIG.1 .

FIG. 2B illustrates a lateral view of the intervertebral cage of FIG. 1.

FIG. 2C illustrates a posterior view of the intervertebral cage andblocking pin of FIG. 1 .

FIG. 2D illustrates a cranial-caudal view of the intervertebral cage ofFIG. 1 .

FIG. 2E illustrates an isometric view of the intervertebral cage of FIG.1 .

FIG. 3 illustrates an exploded view of the intervertebral cage of FIG. 1and associated blocking pin.

FIG. 4A illustrates a side view of the intervertebral cage of FIG. 1 andassociated blocking pin in its manufactured position.

FIG. 4B illustrates a cross-sectional view of the intervertebral cageand blocking pin of FIG. 4A.

FIGS. 5A-5C illustrate various views of the upper plate component of theintervertebral cage of FIG. 1 , in which FIG. 5A illustrates a sideview, FIG. 5B illustrates a partial cutaway view, and FIG. 5Cillustrates a perspective view.

FIGS. 6A-6C illustrate various views of the intermediate articulatingcomponent of the intervertebral cage of FIG. 1 , in which FIG. 6Aillustrates a side view, FIG. 6B illustrates a perspective view, andFIG. 6C illustrates an enlarged view.

FIGS. 7A-7C illustrate various views of the lower plate component of theintervertebral cage of FIG. 1 , in which FIG. 7A illustrates a sideview, FIG. 7B illustrates a partial cutaway view, and FIG. 7Cillustrates a perspective view.

FIGS. 8A and 8B illustrate various views of the blocking pin of FIG. 1 ,in which FIG. 8A illustrates a top-down view and FIG. 8B illustrates aperspective view.

FIGS. 9A-9H illustrate a method of expanding the intervertebral cage ofFIG. 1 , in which FIGS. 9A, 9C, 9E, and 9G, illustrate lateral views ofthe cage over the course of expansion, while FIGS. 9B, 9D, 9F, and 9Hillustrate cross-sectional views of the cage over the course ofexpansion.

FIG. 9I illustrates a partial cutaway posterior view of theintervertebral cage of FIGS. 9C and 9D.

FIG. 9J illustrates a partial cutaway anterior view of theintervertebral cage of FIGS. 9C and 9D.

FIG. 10 illustrates a perspective view of another exemplary embodimentof an intervertebral cage and associated blocking pin in accordance withthe present disclosure.

FIG. 11A illustrates a posterior view of the intervertebral cage of FIG.10 .

FIG. 11B illustrates a lateral view of the intervertebral cage of FIG.10 .

FIG. 11C illustrates an anterior view of the intervertebral cage andblocking pin of FIG. 10 .

FIG. 11D illustrates a cranial-caudal view of the intervertebral cage ofFIG. 10 .

FIG. 11E illustrates an isometric view of the intervertebral cage ofFIG. 10 .

FIG. 12 illustrates an exploded view of the intervertebral cage andassociated blocking pin of FIG. 10 .

FIG. 13A illustrates a side view of the intervertebral cage andassociated blocking pin of FIG. 10 in its manufactured position.

FIG. 13B illustrates a cross-sectional view of the intervertebral cageand blocking pin of FIG. 13A.

FIGS. 14A-14C illustrate various views of the upper plate component ofthe intervertebral cage of FIG. 10 , in which FIG. 14A illustrates aside view, FIG. 14B illustrates a partial cutaway view, and FIG. 14Cillustrates a perspective view.

FIGS. 15A-15D illustrate various views of the intermediate articulatingcomponent of the intervertebral cage of FIG. 10 , in which FIG. 15Aillustrates a side view, FIG. 15B illustrates a perspective view, FIG.15C illustrates a partial cross-sectional view, and FIG. 15D illustratesan enlarged view.

FIGS. 16A and 16B illustrate various views of the blocking pin of FIG.12 , in which FIG. 16A illustrates a top-down view and FIG. 16Billustrates a perspective view.

FIGS. 17A-17J illustrate a method of expanding the intervertebral cageof FIG. 10 , in which:

FIGS. 17A, 17D, and 17F, illustrate lateral views of the cage over thecourse of expansion;

FIGS. 17B, 17E, and 17G illustrate cross-sectional views of the cageover the course of expansion;

FIG. 17C illustrates an enlarged anterior view of the intervertebralcage of FIGS. 17A and 17B;

FIG. 17H illustrates an enlarged anterior view of the intervertebralcage of FIGS. 17F and 17G;

FIG. 17I illustrates a partial cutaway posterior view of theintervertebral cage of FIGS. 17F and 17G;

FIG. 17J illustrates a partial cutaway anterior view of theintervertebral cage of FIGS. 17F and 17G.

DETAILED DESCRIPTION

The present disclosure provides various spinal implant devices, such asinterbody fusion spacers, or cages, for insertion between adjacentvertebrae. The devices can be configured for use in either the cervicalor lumbar region of the spine. In some embodiments, these devices areconfigured as PLIF cages, or posterior lumbar interbody fusion cages.These cages can restore and maintain intervertebral height of the spinalsegment to be treated, and stabilize the spine by restoring sagittalbalance and alignment. In some embodiments, the cages may contain anarticulating mechanism to allow expansion and angular adjustment. Thisarticulating mechanism allows upper and lower plate components to glidesmoothly relative to one another. The cages may have a first, insertionconfiguration characterized by a reduced size at each of their insertionends to facilitate insertion through a narrow access passage and intothe intervertebral space. The cages may be inserted in a first, reducedsize and then expanded to a second, expanded size once implanted. Intheir second configuration, the cages are able to maintain the properdisc height and stabilize the spine by restoring sagittal balance andalignment. It is contemplated that, in some embodiments, theintervertebral cages may also be designed to allow the cages to expandin a freely selectable (or stepless) manner to reach its second,expanded configuration. The intervertebral cages are configured to beable to adjust the angle of lordosis, and can accommodate largerlodortic angles in their second, expanded configuration. Further, thesecages may promote fusion to further enhance spine stability byimmobilizing the adjacent vertebral bodies.

Additionally, the implantable devices may be manufactured usingselective laser melting (SLM) techniques, a form of additivemanufacturing. The devices may also be manufactured by other comparabletechniques, such as for example, 3D printing, electron beam melting(EBM), layer deposition, and rapid manufacturing. With these productiontechniques, it is possible to create an all-in-one, multi-componentdevice which may have interconnected and movable parts without furtherneed for external fixation or attachment elements to keep the componentstogether. Accordingly, the intervertebral cages of the presentdisclosure are formed of multiple, interconnected parts that do notrequire additional external fixation elements to keep together.

Even more relevant, devices manufactured in this manner would not haveconnection seams whereas devices traditionally manufactured would havejoined seams to connect one component to another. These connection seamscan often represent weakened areas of the implantable device,particularly when the bonds of these seams wear or break over time withrepeated use or under stress. By manufacturing the disclosed implantabledevices using additive manufacturing, connection seams are avoidedentirely and therefore the problem is avoided.

In addition, by manufacturing these devices using an additivemanufacturing process, all of the components of the device (that is,both the intervertebral cage and the pins for expanding and blocking)remain a complete construct during both the insertion process as well asthe expansion process. That is, multiple components are providedtogether as a collective single unit so that the collective single unitis inserted into the patient, actuated to allow expansion, and thenallowed to remain as a collective single unit in situ. In contrast toother cages requiring insertion of external screws or wedges forexpansion, in the present embodiments the expansion and blockingcomponents do not need to be inserted into the cage, nor removed fromthe cage, at any stage during the process. This is because thesecomponents are manufactured to be captured internal to the cages, andwhile freely movable within the cage, are already contained within thecage so that no additional insertion or removal is necessary.

In some embodiments, the cages can be made with a portion of, orentirely of, an engineered cellular structure that includes a network ofpores, microstructures and nanostructures to facilitate osteosynthesis.For example, the engineered cellular structure can comprise aninterconnected network of pores and other micro and nano sizedstructures that take on a mesh-like appearance. These engineeredcellular structures can be provided by etching or blasting to change thesurface of the device on the nano level. One type of etching process mayutilize, for example, HF acid treatment. In addition, these cages canalso include internal imaging markers that allow the user to properlyalign the cage and generally facilitate insertion through visualizationduring navigation. The imaging marker shows up as a solid body amongstthe mesh under x-ray, fluoroscopy or CT scan, for example.

Another benefit provided by the implantable devices of the presentdisclosure is that they are able to be specifically customized to thepatient's needs. Customization of the implantable devices is relevant toproviding a preferred modulus matching between the implant device andthe various qualities and types of bone being treated, such as forexample, cortical versus cancellous, apophyseal versus central, andsclerotic versus osteopenic bone, each of which has its own differentcompression to structural failure data. Likewise, similar data can alsobe generated for various implant designs, such as for example, porousversus solid, trabecular versus non-trabecular, etc. Such data may becadaveric, or computer finite element generated. Clinical correlationwith, for example, DEXA data can also allow implantable devices to bedesigned specifically for use with sclerotic, normal, or osteopenicbone. Thus, the ability to provide customized implantable devices suchas the ones provided herein allow the matching of the Elastic Modulus ofComplex Structures (EMOCS), which enable implantable devices to beengineered to minimize mismatch, mitigate subsidence and optimizehealing, thereby providing better clinical outcomes.

Turning now to the drawings, FIG. 1 shows an exemplary embodiment of anexpandable and angularly adjustable articulating intervertebral cage 10of the present disclosure. The intervertebral cage 10 may comprise apair of articulating shells or plate components 20, 40 configured forplacement against endplates of a pair of adjacent vertebral bodies. Inone embodiment, the articulating plate components may include a flatbearing surface for placement against the endplates. Residing in betweenand configured to cooperate with these articulating plate components 20,40 is an intermediate guide component 100 that facilitates movement, andmore specifically, smooth gliding motion, of the plate components 20, 40relative to one another, as will be described below.

As illustrated in greater detail in FIGS. 2A to 2E, in which FIG. 2Ashows the anterior view of the cage 10, FIG. 2B shows the side orlateral view of the cage 10, FIG. 2C shows the posterior view of thecage 10, FIG. 2D shows the cranial-caudal view of the cage 10, and FIG.2E shows the isometric view of the cage 10, the cage 10 may comprise anupper shell or plate component 20 and a bottom shell or plate component40 configured to articulate relative to one another. In the presentembodiment, movement of the plate components 20, 40 can be realized byan articulating joint mechanism residing within and between the platecomponents 20, 40, which mechanism comprises an intermediate guidecomponent 100 that enables the components 20, 40 to roll over oneanother. In other words, the bottom plate component 40 serves as thebase, while the upper plate component 20 rolls over the base 40 to allowsmooth gliding motion between the two components.

FIG. 3 illustrates an exploded view of the assembly of theintervertebral cage 10 and associated blocking pin 60 of the presentembodiment. The upper plate component 20 may comprise a pair of extendedarms or sidewalls 24. Each of the sidewalls 24 may have one or moreridges or teeth 28 along a portion thereof. In between the sidewalls 24an internal cavity 26 (shown in FIG. 5C) may be provided for receivingthe intermediate guide component 100.

Similarly, the base or lower plate component 40 may comprise a pair ofextended sidewalls 46. These extended sidewalls 46 may define a slot orinternal cavity 48 for receiving the intermediate guide component 100therebetween. At the top of the extended sidewalls 46 are one or moreridges or teeth 52 along a portion thereof. As shown in FIG. 4A, theteeth 52 of the lower plate component 40 may be configured to mate with,and articulate relative to, the teeth 28 of the upper plate component20. In some embodiments, the upper plate component 20 and lower platecomponent 40 may be tapered at their free ends at the first, leading end12 of the cage 10, if so desired.

As shown in FIGS. 2A-2E and FIG. 3 , in between and residing within theupper and lower plate components 20, 40 is the intermediate guidecomponent 100 which facilitates the rocking motion of the upper andlower plate components 20, 40 relative to one another. As shown in FIGS.6A and 6B, the intermediate guide component 100 may comprise a glidingor rolling surface 106 facing the upper plate component 20. The lateralsides of the intermediate guide component 100 may include cutoutportions or grooves 120 that may serve as guiding cavities for thearticulation. The intermediate guide component 100 may further includean internal cavity 110 for receiving the blocking pin 60 as well.

As further shown in FIG. 3 and FIGS. 8A and 8B, the blocking pin 60 maycomprise an elongate shaft 64 attached to which is an enlarged pin head68. The pin head 68 may have a locking surface 72, a guiding surface 74and an adjustment surface 76. In use, the pin 60 serves to help tilt, orpivot, the upper plate component 20 relative to the bottom platecomponent or base 40, and also blocks the movement of the components 20,40 once the final configuration has been achieved, so that the positionof the plate components 20, 40 relative to one another may be locked andno further movement occurs.

As mentioned above, the implantable devices of the present disclosuremay be manufactured in such a way that the processing of all componentsinto the final assembled device is achieved in one step bygenerative/additive production techniques (e.g., selective laser melting(SLM) or other similar techniques as mentioned above). FIGS. 4A and 4Billustrate an exemplary manufacturing configuration showing how the cage10 and the blocking pin 60 can be manufactured nested together undersuch a technique. It should be noted how the benefits ofgenerative/additive production techniques may be utilized here toprovide a multi-component assembly with interactive components that donot require any additional external fixation elements to maintain thesesubcomponents intact and interacting with one another. As can be seen,the entire assembly of cage 10 plus blocking pin 60 may be producedaltogether as one unit having movable internal parts.

As previously mentioned, devices manufactured in this manner would nothave connection seams whereas devices traditionally manufactured wouldhave joined seams to connect one component to another. These connectionseams can often represent weakened areas of the implantable device,particularly when the bonds of these seams wear or break over time withrepeated use or under stress. By manufacturing the disclosed implantabledevices using additive manufacturing, one of the advantages with thesedevices is that connection seams are avoided entirely and therefore theproblem is avoided.

FIGS. 5A to 5C illustrate in greater detail the upper plate component 20of the intervertebral cage 10 of the present disclosure. As shown, theupper plate component 20 may comprise a pair of extended arms orsidewalls 24 between which is defined a cavity or slot 26 that isconfigured to receive the intermediate guide component 100. Each of theextended sidewalls 24 may include one or more teeth or ridges 28 along aportion thereof. The teeth 28 may be configured to mate and cooperatewith the teeth 52 of the lower plate component 40, as previouslydescribed. As illustrated, the upper plate component 20 may beconfigured to sit on the lower base plate component 40. The cavity 26may further include a bevel surface 34 as well as a blocking surface 36,which features will be described in more detail below. In addition, asshown, the teeth 28 are formed as part of a thickened portion of theplates 24, with the interior of the thickened portion creating a guidingsurface 30 for the articulation of the plate components 20, 40 andintermediate guide component 100. As shown in the cross-sectional viewof FIG. 5B, the cavity 26 may include a gliding or rolling surface 32.In addition, like lower plate component 40, the upper plate component 20in the present embodiment may also include a bevel surface 34 and ablocking surface 36. In fact, upper plate component 20 may be configuredas a mirror image of lower plate component 40 in some embodiments.

FIGS. 6A to 6C illustrate in greater detail the intermediate guidecomponent 100 of the intervertebral cage 10 of the present disclosure.As shown, the intermediate guide component 100 may comprise a gliding orrolling surface 106 facing the upper plate component 20. The lateralsides of the intermediate guide component 100 may include grooves 120that may serve as guiding cavities for the articulation. Theintermediate guide component 100 may include an internal cavity forreceiving the blocking pin 60, as shown in FIG. 3 .

In addition, the posterior of the intermediate guide component 100 mayinclude a port or channel 116 having an opening 118 for access to theblocking pin 60. Surrounding the channel 116 is an instrument interface130 that allows the attachment of an instrument to the device 10 or pin60 through a bayonet-type attachment. This instrument interface 130 canbe seen in an enlarged detailed view in FIG. 6C. The instrumentinterface 130 may be configured to adapt to a bayonet-type connection toallow a delivery instrument, for example, to be attached to the device10 or blocking pin 60. The instrument interface 130 may include an outercontact surface 132, a bayonet fitting 134, recesses 136 surrounding thechannel or port 116 for instrument insertion, and a cylindrical guidingsurface 138 provided by the channel 116. Collectively, the instrumentinterface 130 provides the necessary structure for attachment to otherinstruments, including delivery instruments for inserting theimplantable device 10 and/or tools for advancing the blocking pin 60.

FIGS. 7A to 7C illustrate in greater detail the lower plate component orbase 40 of the intervertebral cage 10 of the present disclosure. Asshown and as previously discussed, the lower plate component 40 maycomprise a pair of extended sidewalls 46 defining a cavity or slot 48therein. This cavity 48 may be configured to receive the intermediateguide component 100. Like upper plate component 20, the teeth 52 of thelower plate component 40 are provided on a thickened portion of thesidewalls 46, and which thickened portion has on its interior a guidingsurface 50 for the articulation of the components together. The cavity48 may further include a bevel surface 34 as well as a blocking surface36, similar to upper plate component 20. As shown in the cross-sectionalview of FIG. 7B, the cavity 48 may include a gliding or rolling surface58.

FIGS. 8A and 8B illustrate the details of the blocking pin 60 that maybe used with the intervertebral cage 10 of the present disclosure. Theblocking pin 60 may comprise an elongate shaft 64 extending into anenlarged pin head 68. The pin head 68 may have a locking surface 72, aguiding surface 74 and an adjustment surface 76.

FIGS. 9A-9J illustrate the process of expanding and angularly adjustingthe intervertebral cage 10 of the present disclosure. In its initialinsertion stage or configuration, the expandable cage 10 may have acompressed, reduced size whereby the upper plate component 20 and lowerplate component 40 are angled towards one another at the first, leadingend 12 of the cage 10 or towards the anterior, as shown in FIGS. 9A and9B. This creates a tapered nose or leading tip, and the slimmest profile(i.e., the smallest anterior height) to facilitate insertion, which isparticularly beneficial to traverse the narrow access path to theimplant site. In some embodiments, the ends of the plate components 20,40 can also include a bevel or taper, if desired. The plate components20, 40 may each include flat external bearing surfaces to contact andpress against the endplates of the vertebral bodies.

One of the advantages of the interlocking teeth 28, 52 of the upper andlower plate components 20, 40, respectively, is that the movement of thecomponents 20, 40 are achieved in a uniform, smooth motion. In otherwords, the movement of the plate components 20, 40 is synchronized bythe ratcheting motion of the two plate components 20, 40 against oneanother. In the present configuration, no active adjustment is beingeffected.

The blocking pin 60, which may be additively manufactured to residewithin the intermediate guide component 100 itself in a first insertionconfiguration, does not interfere with the pivoting of the platecomponents 20, 40, and can be considered in a non-active state at thispoint. As shown, the blocking pin 60 rests within the cavity 110 of theintermediate guide component 100 but does not in this configuration abutthe bevel surfaces 34, 54 or blocking surfaces 36, 56 of the platecomponents 20, 40.

FIGS. 9C and 9D show the cage 10 in an intermediate position orconfiguration. In this configuration, the upper and lower platecomponents 20, 40 are parallel to one another, and defines the smallestinsertion height possible for the intervertebral cage 10. Note that theblocking pin 60 has advanced anteriorly from the second, trailing end 14of the cage 10 towards the first, leading end 12 in this intermediateconfiguration, and that the enlarged head 68 is urging against the upperand lower plate components 20, 140. Once the cage 10 has passed throughthe narrow access path and into the intervertebral/intradiscal space,the blocking pin 60 may continue to be advanced, as shown in FIGS. 9Eand 9F. The advancement of the blocking pin 60 anteriorly or towards thefirst, leading end 12 results in the synchronous spreading apart of theupper plate component 20 relative to the lower plate component 40 by arolling mechanism of the interlocking teeth 28, 52. This rollingmovement is facilitated by the smooth gliding or guiding surfaces 32, 58of the plate components 20, 40 against the intermediate guide component100. The plate components 20, 40 become angled or partially open, withthe anterior height at the first, leading end 12 being greater than theposterior height at the second, trailing end 14, as shown.

FIGS. 9G and 9H show the cage 10 continuing in its active adjustmentphase and load transfer at the posterior end of the cage 10. As theblocking pin 60 is advanced anteriorly, the plate components 20, 40continue to be angled towards the posterior at the second, trailing end14 and increasingly open towards the anterior at the first, leading end12. As shown, the cage 10 may now have the greatest anterior heightpossible when fully adjusted, which is when the blocking pin 60 is atits anterior-most position within the intermediate guide component 100.In this configuration, the load is transferred to the posterior of thecage 10 and the cage 10 is fully expanded or adjusted, and in itsblocked or locked position. In this final, expanded position, the cage10 is effective in accommodating the lordosis angle of the vertebralsegment, and can restore sagittal balance and alignment to the spine.The plate components 20, 40 are configured to press against theendplates of the vertebral bodies and can now immobilize and stabilizethis region.

FIGS. 9I and 9J show various partial cutaway views of the fully expandedcage 10. These views illustrate the cooperation of the guiding surfaces32, 50 of the thickened portions of the upper and lower base components20, 40 within the guiding cavity or groove 120 of the intermediate guidecomponent 100. This feature ensures that the compounded structureremains intact during the articulation process. That is, the teeth 28,52 interlock together while the guiding surfaces 32, 50 also interlockwithin the guiding cavities 120 so as to stay fitted together whilemovement occurs. Meanwhile, the rolling motion achieved by thesefeatures is smooth and synchronous.

FIG. 10 shows another exemplary embodiment of an expandable andangularly adjustable articulating intervertebral cage 210 of the presentdisclosure. The intervertebral cage 210 shares many similar features andbenefits of the intervertebral cage 10 previously discussed, includinghaving a pair of articulating shell or plate components 220, 240configured for placement against endplates of a pair of adjacentvertebral bodies. In one embodiment, the articulating plate components220, 240 may include a flat bearing surface for placement against theendplates. Residing in between and configured to cooperate with thesearticulating plate components 220, 240 is an intermediate guidecomponent 300 that facilitates movement, and more specifically, smoothgliding motion, of the plate components 220, 240 relative to oneanother. This intermediate guide component 300 is configured to receivean actuator pin 260 that, as it is advanced anteriorly, enables theupper and lower plate components 220, 240 to smoothly roll against oneanother and adjust the angle of the anterior end, or first leading end212 of the intervertebral cage 210.

As illustrated in greater detail in FIGS. 11A to 11E, in which FIG. 11Ashows the posterior view of the cage 210, FIG. 11B shows the side orlateral view of the cage 210, FIG. 11C shows the anterior view of thecage 210, FIG. 2D shows the cranial-caudal view of the cage 210, andFIG. 2E shows the isometric view of the cage 210, the cage 210 maycomprise an upper plate component 220 and a bottom plate component 240configured to articulate relative to one another. In the presentembodiment, movement of the plate components 220, 240 can be realized bythis intermediate guide component 300 which serves as an articulatingjoint mechanism cooperating with these plate components 220, 240,allowing the plate components 220, 240 to roll over one another. Inother words, the bottom plate component 240 serves as the base, whilethe upper plate component 220 rolls over the base 240 to allow smoothgliding motion between the two plate components 220, 240. An actuatorpin 260 that serves to block the movement of the plate components 220,240 is provided and is configured to movably reside in the intermediateguide component 300.

FIG. 12 illustrates an exploded view of the assembly of theintervertebral cage 210 and associated actuator pin 60 of the presentembodiment. The upper plate component 220 may comprise a pair ofextended arms or sidewalls 224. In between the sidewalls 224 an internalcavity 226 may be provided for accommodating the intermediate guidecomponent 300. Similarly, the base or lower plate component 240 maycomprise a pair of extended sidewalls 246. These extended sidewalls 142may define a slot or internal cavity 248 for accommodating theintermediate guide component 300. The upper plate component 220 andlower plate component 240 may be tapered at their free ends at thefirst, leading end 212 of the cage 210, if so desired.

In between and residing inside the upper and lower plate components 220,240 is an intermediate guide component 300 that facilitates the rollingmotion of the upper and lower plate components 220, 240 relative to oneanother. The intermediate guide component 300 may comprise a pair ofopposed ratcheting surfaces 306 facing the upper and lower platecomponents 220, 240. These ratcheting surfaces 306 have on a portionthereof a series of teeth 308. The lateral sides of the intermediateguide component 300 may include grooves 320 that may serve as guidingcavities for the articulation, similar to the ones described above. Theintermediate guide component 300 may include a port 316 with an opening318 for access to the actuator pin 260.

As further shown in FIGS. 16A and 16B, the actuator pin 260 may comprisean elongate shaft 264 extending into an enlarged pin head 268. The pinhead 268 may have a blocking surface 272, and an adjustment surface 276.In addition, the pin head 268 may include a ratcheting groove 270 on thesides thereof, which will be explained in detail later. Around the shaft264 a flange can be provided 266, as shown. Like blocking pin 60, theactuator pin 260 serves to help tilt, or pivot, the upper platecomponent 220 relative to the bottom plate component or base 240, andalso blocks the movement of the components 220, 240 once the finalconfiguration has been achieved, so that the relative positions of theupper and lower plate components 220, 240 may be locked and no furthermovement is possible.

As mentioned above, the implantable devices of the present disclosuremay be manufactured in such a way that the processing of all componentsinto the final assembled device is achieved in one step bygenerative/additive production techniques (e.g., selective laser melting(SLM) or other similar techniques as mentioned above). FIGS. 13A and 13Billustrate an exemplary manufacturing configuration showing how the cage210 and the actuator pin 260 can be manufactured nested together undersuch a technique. It should be noted how the benefits ofgenerative/additive production techniques may be utilized here toprovide a multi-component assembly with interactive components that donot require any additional external fixation elements to maintain thesesubcomponents intact and interacting with one another. As can be seen,the entire assembly of cage 210 plus actuator pin 260 may be producedaltogether as one unit having movable internal parts.

FIGS. 14A to 14C illustrate in greater detail the upper plate component220 of the intervertebral cage 210 of the present disclosure. As shown,the upper plate component 220 may comprise a pair of extended arms orsidewalls 224 between which is defined an internal cavity or slot 226that is configured to receive the pin 260 as well as cooperate with theintermediate guide component 300. On the interior side of the sidewalls224 are elongate slots 252 that cooperate with the finger projections302 of the intermediate guide component 300, as will be described ingreater detail below.

Within the interior of the upper plate component 220 are one or moreteeth or ridges 228. The teeth 228 may be configured to mate andcooperate with the teeth 308 of the intermediate guide component 300. Asillustrated, the upper plate component 220 may be configured to sit onthe lower base plate component 240. The cavity 226 may further include abevel surface 234 as well as a blocking surface 236, which features willbe described in more detail below. As shown in the cross-sectional viewof FIG. 14B, the internal cavity 226 may include a gliding or rollingsurface 232. The underside of upper plate component 220 also includescavities or recesses 222 configured to receive in a snap-fit connectionthe raised guides 322 of the intermediate guide component 300 forlateral stabilization of the plates, and a cavity 238 that allows forsnap-in attachment of the knobs 304 of the finger projections 302 of theintermediate guide component 300.

It should be understood that, while the interior of the lower platecomponent 240 is not shown here, the lower plate component 240 can beconsidered a mirror image of the upper plate component 220. As such, allfeatures provided for the upper plate component 220 would be providedfor the lower plate component 240 as well.

FIGS. 15A to 15D illustrate in greater detail the intermediate guidecomponent 300 of the intervertebral cage 210 of the present disclosure.As shown, the intermediate guide component 300 may comprise a pair ofgliding or rolling surfaces 306 facing the upper plate component 220 andlower plate component 240. The lateral sides of the intermediate guidecomponent 300 may include grooves 320 that may serve as guiding cavitiesfor the articulation. An internal cavity 310 is configured to receivethe actuator pin 260. An extended lip 324 may be provided, as shown inFIG. 15C, to abut against the flange 266 of the shaft 264 of theactuator pin 260 to prevent overextension. At the anterior portion ofthe intermediate guide component 300 are snapper arms 312 having attheir terminal ends on an interior surface a notch 314 to facilitatelocking. Flanking the snapper arms 312 and spaced apart therefrom arefinger projections 302 that have at their terminal ends on theirexterior surface a knob 304 for snap-fit engagement with the recesses238 of the upper and lower plate components

In addition, at the posterior portion of the intermediate guidecomponent 300 is a port or channel 316 with an opening 318 for access tothe actuator pin 260. Surrounding the channel 316 is an instrumentinterface 330 that allows the attachment of an instrument to the pin 260through a bayonet-type attachment. This instrument interface 230 can beseen in an enlarged detailed view in FIG. 15D. The instrument interface330 may be configured to adapt to a bayonet-type connection to allow adelivery instrument, for example, to be attached to the cage 210 or theactuator pin 260. The instrument interface 330 may include an outercontact surface 332, a bayonet fitting 334, and recesses 336 surroundingthe channel or port 316 for instrument insertion, which channel 316provides a cylindrical guiding surface surrounding the opening 318 ofthe channel 316 for instrument attachment. Collectively, the instrumentinterface 330 provides the necessary structure for attachment to otherinstruments, such as for delivery of the cage 210 or the actuation ofthe actuator pin 260. Raised guides 322 are provided on the rollingsurface 306 of the intermediate guide component 300 near the posteriorportion, as shown in FIG. 15D, which guides 322 may be received in therecesses 222 of the upper plate component 220.

FIGS. 16A and 16B illustrate the details of the actuator pin 260 thatmay be used with the intervertebral cage 210 of the present disclosure.The actuator pin 260 may comprise an elongate shaft 264 extending intoan enlarged pin head 268. The pin head 268 may have a blocking surface272 and an adjustment surface 276. In addition, the sides of theenlarged pin head 268 may include a groove 270 for locking engagement ofthe actuator mechanism. At the free end of the shaft 264 is a flange 266that cooperates with the extended lip 324 of the intermediate guidecomponent 300.

FIGS. 17A-17J illustrate the process of expanding and angularlyadjusting the intervertebral cage 210 of the present disclosure. In itsinitial insertion stage or configuration, the expandable cage 210 mayhave a compressed, reduced size whereby the upper plate component 220and lower plate component 240 are angled towards one another at thefirst, leading end 212 of the cage 210 or towards the anterior, as shownin FIGS. 17A to 17C. This creates a tapered nose or leading tip, and theslimmest profile (i.e., the smallest anterior height) to facilitateinsertion, which is particularly beneficial to traverse the narrowaccess path to the implant site. In some embodiments, the ends of theplate components 220, 240 can also include a bevel or taper, if desired.The plate components 220, 240 may each include flat external bearingsurfaces to contact and press against the endplates of the vertebralbodies.

One of the advantages of the internal teeth 228 of the plate components220, 240 interlocked with the teeth 308 on the rolling surface 306 ofthe intermediate guide component 300 is that the movement of thecomponents 220, 240 are achieved in a uniform, smooth motion. In otherwords, the movement of the plate components 220, 240 is synchronized. Inthe present configuration, no active adjustment is being effected. Asfurther shown in FIG. 17C, in the initial insertion configuration, theknobs 304 of the finger projections 302 are held in position relative tothe upper plate component 220 by being snap-fitted in the recesses 238provided on the interior of the component 220.

As the actuator pin 260 is advanced anteriorly or towards the first,leading end 212, the cage 210 transitions into an intermediate positionor configuration. In this intermediate configuration, the upper andlower plate components 220, 240 are parallel to one another, and definesthe smallest insertion height possible for the intervertebral cage 210.This configuration can be seen in FIGS. 13A and 13B. During thetransition, the enlarged head 268 is urging against the upper and lowerplate components 220, 240. Once the cage 210 has passed through thenarrow access path and into the intervertebral/intradiscal space, theactuator pin 260 may continue to be advanced, as shown in FIGS. 17D to17E. The advancement of the actuator pin 260 anteriorly or towards thefirst, leading end 212 from the second, trailing end 214 results in thesynchronous spreading apart of the upper plate component 220 relative tothe lower plate component 240 by a rolling mechanism achieved by thecombination of the ratcheting of the teeth 228, 308 together, as well asthe smooth gliding or movement of the guiding surfaces 232 of the platecomponents 220, 240 against the intermediate guide component 300, andthe gliding of the finger projections 302 within the elongate slot 252of the upper plate component 220 and corresponding slot of the lowerplate component 240 in a rail-like fashion. The plate components 220,240 become angled or partially open, with the anterior height at thefirst, leading end 212 being greater than the posterior height at thesecond, trailing end 214, as shown.

FIGS. 17D and 17E show the cage 210 continuing in its active adjustmentphase and load transfer at the posterior end or second, trailing end 214of the cage 210. As the actuator pin 260 is advanced anteriorly, theplate components 220, 240 continue to be angled towards the posteriorand increasingly open towards the anterior. As shown in FIGS. 17F to17J, the cage 210 may now have the greatest anterior height possiblewhen fully adjusted, which is when the actuator pin 260 is at itsanterior-most position. In this configuration, the load is transferredto the posterior or second, trailing end 214 of the cage 210 and thecage 210 is fully expanded or angularly adjusted, and in its blocked orlocked position. As shown in FIG. 17H, the rail or notch 314 on thesnapper arms 312 which cooperate with the groove 270 on the actuator pin260 are now interlocked with the groove 270 on the enlarged head 268 ofthe actuator pin 260, thereby preventing further movement anteriorly ofthe actuator pin 260 within the intermediate guide component 300. Inthis final, expanded position, the cage 210 is effective inaccommodating the lordosis angle of the vertebral segment, and canrestore sagittal balance and alignment to the spine. The platecomponents 220, 240 are configured to press against the endplates of thevertebral bodies and can now immobilize and stabilize this region.

FIGS. 17I and 17J show various partial cutaway views of the fullyexpanded cage 310. These views illustrate the cooperation of the teethin the ratcheting mechanism, the gliding of the finger projectionswithin the elongate slots, the guiding surfaces within the groove of theintermediate guide component, and the notch on the snapper arms withinthe groove of the actuator pin. Collectively, these features ensure thatthe compounded structure remains intact during the articulation processso as to stay fitted together while angular adjustment and movementoccurs. Furthermore, the features provided herein enable smooth glidingmovement while the cage 210 is adjusted and blocked from further angularmovement or expansion.

As mentioned above, the intervertebral cages 10, 210 of the presentdisclosure are configured to be able to allow insertion through a narrowaccess path, but are able to be expanded and angularly adjusted so thatthe cages are capable of adjusting the angle of lordosis of thevertebral segments. By being able to smoothly roll at the articulatingjoint, the upper plate components 20, 220 may effectively see-sawrelative to the base or lower plate components 40, 240 to allow a verynarrow anterior for insertion and a larger anterior after implantationto accommodate and adapt to larger angles of lordosis. Additionally, thecages 10, 210 can effectively restore sagittal balance and alignment ofthe spine, and can promote fusion to immobilize and stabilize the spinalsegment.

With respect to the ability of the expandable cages 10, 210 to promotefusion, many in-vitro and in-vivo studies on bone healing and fusionhave shown that porosity is necessary to allow vascularization, and thatthe desired infrastructure for promoting new bone growth should have aporous interconnected pore network with surface properties that areoptimized for cell attachment, migration, proliferation anddifferentiation. At the same time, there are many who believe theimplant's ability to provide adequate structural support or mechanicalintegrity for new cellular activity is the main factor to achievingclinical success, while others emphasize the role of porosity as the keyfeature. Regardless of the relative importance of one aspect incomparison to the other, what is clear is that both structural integrityto stabilize, as well as the porous structure to support cellulargrowth, are key components of proper and sustainable bone regrowth.

Accordingly, these cages 10, 210 may take advantage of current additivemanufacturing techniques that allow for greater customization of thedevices by creating a unitary body that may have both solid and porousfeatures in one. In some embodiments, the cages 10, 210 can have aporous structure, and be made with an engineered cellular structure thatincludes a network of pores, microstructures and nanostructures tofacilitate osteosynthesis. For example, the engineered cellularstructure can comprise an interconnected network of pores and othermicro and nano sized structures that take on a mesh-like appearance.These engineered cellular structures can be provided by etching orblasting to change the surface of the device on the nano level. One typeof etching process may utilize, for example, HF acid treatment. Thesesame manufacturing techniques may be employed to provide these cageswith an internal imaging marker. For example, these cages can alsoinclude internal imaging markers that allow the user to properly alignthe cage and generally facilitate insertion through visualization duringnavigation. The imaging marker shows up as a solid body amongst the meshunder x-ray, fluoroscopy or CT scan, for example. A cage may comprise asingle marker, or a plurality of markers. These internal imaging markersgreatly facilitate the ease and precision of implanting the cages, sinceit is possible to manufacture the cages with one or more internallyembedded markers for improved visualization during navigation andimplantation.

Another benefit provided by the implantable devices of the presentdisclosure is that they are able to be specifically customized to thepatient's needs. Customization of the implantable devices is relevant toproviding a preferred modulus matching between the implant device andthe various qualities and types of bone being treated, such as forexample, cortical versus cancellous, apophyseal versus central, andsclerotic versus osteopenic bone, each of which has its own differentcompression to structural failure data. Likewise, similar data can alsobe generated for various implant designs, such as for example, porousversus solid, trabecular versus non-trabecular, etc. Such data may becadaveric, or computer finite element generated. Clinical correlationwith, for example, DEXA data can also allow implantable devices to bedesigned specifically for use with sclerotic, normal, or osteopenicbone. Thus, the ability to provide customized implantable devices suchas the ones provided herein allow the matching of the Elastic Modulus ofComplex Structures (EMOCS), which enable implantable devices to beengineered to minimize mismatch, mitigate subsidence and optimizehealing, thereby providing better clinical outcomes.

A variety of spinal implants may be provided by the present disclosure,including interbody fusion cages for use in either the cervical orlumbar region of the spine. Although only a posterior lumbar interbodyfusion (PLIF) device is shown, it is contemplated that the sameprinciples may be utilized in a cervical interbody fusion (CIF) device,a transforaminal lumbar interbody fusion (TLIF) device, anterior lumbarinterbody fusion (ALIF) cages, lateral lumbar interbody fusion (LLIF)cages, and oblique lumbar interbody fusion (OLIF) cages.

Other embodiments of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of thedisclosure provided herein. It is intended that the specification andexamples be considered as exemplary only.

What is claimed is:
 1. An expandable spinal implant, comprising: anupper plate component configured for placement against an endplate of afirst vertebral body and a lower plate component configured forplacement against an endplate of a second, adjacent vertebral body; anarticulating mechanism connecting the upper and lower plate componentstogether and comprising an intermediate guide component having aninternal cavity for receiving an actual pin; and an actuator pincomprising a shaft and an enlarged head portion, the actuator pin beingconfigured to move within the intermediate guide component to effectangular adjustment of the expandable spinal implant.
 2. The expandablespinal implant of claim 1, wherein the spinal implant including theactuator pin is manufactured by an additive production technique.
 3. Theexpandable spinal implant of claim 1, wherein the actuator pin ismanufactured to reside inside the upper and lower plate components andintermediate guide component of the expandable spinal implant.
 4. Theexpandable spinal implant of claim 1, wherein each of the upper andlower plate components comprises a pair of extended sidewalls, eachsidewall having a thickened portion containing a guiding surface on aninterior surface.
 5. The expandable spinal implant of claim 4, whereinthe guiding surfaces of the upper and lower plate components areconfigured to move against a guiding cavity on the intermediate guidecomponent.
 6. The expandable spinal implant of claim 4, wherein each ofthe thickened portions contain one or more teeth on a portion thereof.7. The expandable spinal implant of claim 6, wherein the teeth of theupper and lower plate components are configured to interlock with oneanother.
 8. The expandable spinal implant of claim 1, wherein thearticulating mechanism allows rolling movement of the upper and lowerplate components relative to one another.
 9. The expandable spinalimplant of claim 1, wherein each of the upper and lower plate componentsincludes a rolling surface on its interior, the rolling surface beingconfigured to smoothly glide over a top or bottom surface of theintermediate guide component.
 10. The expandable spinal implant of claim1, wherein each of the upper and lower plate components includes aseries of teeth on its interior, the teeth being configured to ratchetover a series of teeth on the top or bottom surface of the intermediateguide component.
 11. The expandable spinal implant of claim 1, whereinthe actuator pin locks the upper and lower plate components together atits anterior-most position.
 12. The expandable spinal implant of claim1, wherein the upper and lower plate components are tapered at one oftheir free ends.
 13. The expandable spinal implant of claim 1, whereinthe posterior end of the cage is configured with an instrumentinterface.
 14. The expandable spinal implant of claim 1, wherein theintermediate guide component is configured to slide in relation toelongate slots on the upper and lower plate components.
 15. Theexpandable spinal implant of claim 1, wherein the intermediate guidecomponent includes raised protrusions that are configured for snap-fitengagement with cavities within the upper and lower plate components.16. The expandable spinal implant of claim 1, further being configuredas a PLIF cage.
 17. The expandable spinal implant of claim 1, furtherhaving a first configuration wherein the plate components are angledtoward one another at an anterior portion of the spinal implant.
 18. Theexpandable spinal implant of claim 1, further having an intermediateconfiguration wherein the plate components are parallel to one another.19. The expandable spinal implant of claim 14, further having a secondconfiguration wherein the plates are locked together and are angledtoward one another at a posterior portion of the spinal implant.
 20. Theexpandable spinal implant of claim 19, wherein in the secondconfiguration, the implant adjusts the angle of lordosis.